Authorities said the fire started in a second-floor bedroom.Ashley Peskoe/NJ.com

NEPTUNE CITY – A blaze that started in the second-floor apartment of a double rental complex early Sunday morning left five people displaced from their home, authorities said.

The fire started at around 3:05 a.m. in the upstairs bedroom of the Locust Avenue home and spread to the attic, Director of Public Safety Edward Kirschenbaum said. The second-floor suffered heavy fire damage.

The blaze was extinguished at around 4 a.m. and the scene was cleared by 5:30 a.m., Kirschenbaum said.

Two families lived in the home, three people upstairs including an elderly woman, and two people downstairs, Kirschenbaum said. At least one family was using assistance from the Red Cross, Kirschenbaum said.

Fire departments from Neptune City and Avon, along with police Sgt. James Clayton and Patrolman Thomas Holmstedt responded to the blaze.

The cause of the fire remains under investigation by the Neptune City Detective Bureau and the Monmouth County Fire Marshal.